The Dangers and Symptoms of Anal Cancer

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Anal cancer is an insidious and growing concern among people living with HIV, especially among gay and bisexual men. Symptoms can start out subtly at first, often with itching around the anus, much like the itching one might associate with hemorrhoids.

An elderly man talking to his doctor about some recent test results.
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Later it can become painful or exhibit signs of bleeding. Eventually, a cancerous lesion can open, resulting in what is known as malodorous drainage. Unfortunately, this is the point when most people finally decide to see a doctor, by which time the cancer is usually quite advanced.

Cancer is defined as an abnormal growth of cells that continue to multiply without the biological means to stop it. Anal cancer is a malignancy occurring in the anus, typically manifesting with a tumorous lesion. Anal cancers tend to develop in the mucosal tissue of the anus or in the anal margin that merges with the skin.

Anal cancer is of growing concern among people living with HIV. In the general population, anal cancer is considered rare, about two per 100,000 people (2016 data). However, in men who have sex with men (MSM), the incidence climbs to as high as 144 cases per 100,000. Moreover, MSM who are HIV-positive are at a much higher risk of getting anal cancer than MSM who are HIV-negative.

While we don't entirely understand why this is, it is believed that the chronic inflammation associated with HIV infection literally ages a cell before its time. When this happens, we will often see cancers developing in people with HIV 10 to 15 years before they would happen in the general population. Anal cancer is among the many cancers believed to be associated with this.

Risk Factors

There is a close association between anal cancer and the human papillomavirus (HPV), the virus which not only causes genital warts but is also associated with the development of cervical cancer.

In addition to HPV and HIV, commonly cited risk factors include smoking, multiple sexual partners, receptive anal sex, a history of hemorrhoids, and anal fissures or fistulas.

Signs and Symptoms

One of the things that make anal cancer so dangerous is that many people show few, if any, symptoms prior to diagnosis. More concerning yet, people will often delay seeing a doctor out of embarrassment, particularly if symptoms don't appear serious.

If symptoms are present they often include:

  • Warts on the anus or genitals
  • Sores or bumps around the anus or in the anal canal
  • Itching in and around the anus
  • Discharge or bleeding from the anus
  • Pain or pressure around the anus
  • Painful areas around the anus in the absence of visible bumps or lesions
  • Open sores around the anus that don't heal


Many experts now recommend routine anal cancer screening for people at high risk.  Recommended tests include a yearly visual and digital exam, as well as a yearly anal Pap smear.

The latter takes a swab of cells from inside the anus and examines them beneath the microscope to identify cellular changes consistent with anal cancer. Abnormal Pap smears are typically followed with high-resolution anoscopy (anal scope) or biopsy.


The treatment of anal cancer depends largely on how advanced the cancer is. After an evaluation to determine the disease stage, a treatment plan is made with a board-certified oncologist.

In the case of a squamous cell carcinoma (SCC), chemotherapy and radiation are often recommended as first-line treatment. In the event of adenocarcinoma, treatment may also include surgery.


Since HPV is considered the prime risk factor for the development of anal cancer, prevention should be largely focused on HPV avoidance. The HPV vaccination is recommended for children and younger people, given in three shots over a six-month period. The Centers for Disease Control and Prevention currently recommends vaccination for the following groups:

  • All children 11 or 12 years of age (age nine is the earliest the vaccine can be given)
  • Teenage boys and girls who did not start or finish the HPV series when they were younger
  • Young men and women through the age of 26

High-risk individuals (such as HIV positive men who engage in receptive anal sex with other men) should be advised to use condoms with each and every sexual encounter and to reduce the number of sex partners.

In addition, anyone with a history of benign lesions should be monitored on a regular basis. An anal Pap can detect early cellular changes consistent with the development of anal cancer, allowing for early intervention and reducing the risk of disease progression.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. Signs and symptoms of anal cancer.

  2. National Institute of Health, National Cancer Institute. Anal cancer treatment (PDQ®)–patient version.

  3. National Institutes of Health, National Cancer Institute. Cancer stat facts, anal cancer.

  4. Patel P, Bush T, Kojic EM, et al. Prevalence, incidence, and clearance of anal high-risk human papillomavirus infection among HIV-infected men in the SUN study. J Infect Dis. 2018;217(6):953-963. doi:10.1093/infdis/jix607

  5. Koskan AM, Brennhofer SA, Helitzer DL. Screening for anal cancer precursors among patients living with HIV in the absence of national guidelines: practitioners' perspectives. Cancer Causes Control. 2019;30(9):989-996.

  6. Glynne-jones R, Saleem W, Harrison M, Mawdsley S, Hall M. Background and current treatment of squamous cell carcinoma of the anus. Oncol Ther. 2016;4(2):135-172. doi:10.1007/s40487-016-0024-0

  7. Centers for Disease Control and Prevention. Human Papillomavirus (HPV): Vaccinating boys and girls.

Additional Reading
  • Department of Veteran Affairs. "Anal Dysplasia and HIV: Primary Care for Veterans with HIV." Washington, D.C.

  • Goldstone, S. "Prevalence of and Risk Factors for Human Papillomavirus (HPV) Infection Among HIV-Seronegative Men Who Have Sex With Men." Journal of Infectious Diseases. 203 (1): 66-74.

  • Hleyhel, M.; Belot, A.; Bouvier, A., et al. "Risk of AIDS-defining cancers in HIV-1 infected patients (1992-2009): results from FHDH-ANRS CO4." Journal of the International AIDS Society.& 15(4).

By Mark Cichocki, RN
Mark Cichocki, RN, is an HIV/AIDS nurse educator at the University of Michigan Health System for more than 20 years.